Eucalyptus globulus subsp bicostata

Eucalyptus globulus subsp bicostata, synonymous with E. bicostata, is one of the large trees that populate the vast mountainous forests of southeast Australia and Tasmania. In this country, the Southern Blue Gum is a valuable forest species, with multiple uses: timber production, paper pulp production, essential oils and homeopathic medicines production, highly fragrant honey, juvenile foliage for bouquets, etc. In our country, its more ornamental stance quickly makes it a very noticeable tree in the garden, hence the choice of a location in line with its stature. Undemanding and attractive all year round, this beautiful evergreen tree is perfect installed in a large garden or a park, isolated or in groups to form a grove.

Eucalyptus globulus subsp. bicostata is a subspecies endemic to southeast Australia, particularly coastal forests and mountainous regions ranging from eastern New South Wales to the Carrai plateau, east, south and central Victoria and Tasmania. Belonging to the Myrtaceae family, it is sometimes called: Southern Blue Gum, Eurabbie or Victorian Blue Gum. Referring to the shape of the fruit, the name Eucalyptus globulus subsp. bicostata comes from the Latin globulus which means globe or ball (round fruit) and bicostatus which means two-ribbed (fruit with 2 operculums).

This eucalyptus forms a large tree, with an erect habit, a straight trunk and a conical crown. Fast-growing, in its natural space, it reaches a height of 40 to 50 m (131 ft 2 in to 164 ft) and 10 to 15 m (32 ft 10 in to 49 ft 2 in) in width. In our climates, its slightly more moderate size hardly exceeds 25 to 30 m (82 to 98 ft 5 in) in height. It generally rises on a single trunk which starts from a stump named lignotuber* located just below the surface of the soil. When young, it displays square and winged branches, carrying juvenile foliage, composed of opposite, elliptical to ovate leaves, 5 to 11 cm (2 to 4.3 in) long for 3 to 6 cm (1.2 to 2.4 in) wide, glaucous green above, waxy and whitish on the reverse. Then, as it develops, the leaves are petiolate, alternate and take a lanceolate to crescent shape, 15 to 40 cm (5.9 to 15.7 in) long and 2.5 to 6 cm (1 to 2.4 in) wide, a nice bright green. The leaves are very aromatic and give off a menthol scent when crushed, rich in eucalyptol. With age, the thick bark, peels off in long strips, revealing a smooth white or greyish underlayer. Flowering occurs from January to March, on plants a few years old. The inflorescence, arranged in the axil of the leaves, is composed of 3 floral buds gathered in a tight bouquet and blossom into small flowers with numerous cream anthers, forming a pompom about 2 cm (0.8 in) in diameter. Rich in nectar, they are very attractive to bees and birds. After flowering, the fruits, called "gumnuts", appear in the form of a woody capsule, hemispherical with two longitudinal ridges, attached to the branch without petiole. Of a beautiful whitish-grey colour, they remain attached to the stem for a long time.

This eucalyptus has a *lignotuber, consisting of a swelling rich in starch that forms on the roots just below the surface of the soil. This organ allows it to grow again from the stump in case of severe frost, fire or cutting to the ground. The plant also produces numerous shoots from dormant buds located under its bark, allowing it to respond very well to coppicing, topping or more severe pruning.

The Southern Blue Gum finds a place in a large garden planted in isolation in a clear space to appreciate the beauty of its bark and the elegance of its foliage. In order to highlight its architectural habit, it is grown on a single trunk. With a hardiness of around -7 to -9°C (19.4 to 15.8 °F), it will prefer a temperate, coastal climate, with dry to moist, well-drained soil.